U.S. Pat. No. 4,731,267 which issued to Makus and Bennett in 1988 discloses a delivery system for wood preservative. The delivery system consists of a pouch filled with wood preservative chemical that is designed to be wrapped around a base of a pole. The pouch is slit to wrapping around a pole, in order to permit the wood preservative to leak out into the wood. The slits are sized to enable the wood preservative to treat the wood over a prolonged period of time.
This delivery system has been quite successful, but has some inherent problems. The pouch used must be of a size that fits the pole. If the pouch is too small to go around the entire circumference of the pole, the treatment is ineffective. If the pouch is too large, there is a danger that excess wood preservative chemicals will run down the pole and leach into the soils causing environmental damage. To ensure that the proper size is available, the pouch is available in sizes that start at 30 inches and increase in length by 6 inch increments up to 72 inches.